解决nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)

今天在ubuntu10.04上面安装nginx，安装完成之后尝试启动nginx，使用命令：

sudo /etc/init.d/nginx start

结果提示错误：

hankcs@ubuntu:~$ sudo /etc/init.d/nginx start
[sudo] password for hankcs:
* Starting nginx nginx nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] bind() to [::]:80 failed (98: Address already in use)
nginx: [emerg] still could not bind()

我看了一下端口占用情况，并且尝试杀了进程：

hankcs@ubuntu:~$ netstat -ntpl
（并非所有进程都能被检测到，所有非本用户的进程信息将不会显示，如果想看到所有信息，则必须切换到 root 用户）
激活Internet连接 (仅服务器)
Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name
tcp 0 0 127.0.0.1:53 0.0.0.0:* LISTEN -
tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN -
hankcs@ubuntu:~$ killall -9 nginx
nginx：没有发现操作

遇到这种问题我先用中文搜索了一下答案，发现大家都在装逼地说要杀nginx重复的进程。我试了下发现是扯淡，于是看了谷歌搜到的第一个英文页面，老外说是nginx先监听了ipv4的80端口之后又监听了ipv6的80端口，于是就重复占用了。更加坑人的是你去看了端口占用它又把80端口释放了，是不是很囧。

解决方案是编辑nginx的配置文件

hankcs@ubuntu:~$ sudo gedit /etc/nginx/sites-available/default

修改这一段：

listen 80;
listen [::]:80 default_server;

为

listen 80;
listen [::]:80 ipv6only=on default_server;

然后启动nginx，完美解决！